Compressor apparatus



April 22,1958 G. E. GIACCHINO 2,831,629

COMPRESSOR APPARATUS Filed May a, 1952 FIG. 2.

FIG. if

WITNESSES: INVENTOR GEORGE E. GIACCHINO i 63H. Q 38 RM ATTORN EY United States PatentO CONIPRESSOR APPARATUS George E. Giacchino, Drexel Hill, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 6, 1952, Serial No. 286,308

3 Claims. (Cl. 230-122) This invention relates to rotary compressors, and has for an object the provision of improved means for increasing the useful operating range of an axial-flow compressor of the type generally associated with a gas turbine power plant.

Compressor surging and blade vibration problems have been encountered in the operation of high pressure ratio compressors of the axial-flow type, which may be designed to attain maxim-um efiiciency at predetermined rotative speed and pressure ratio. It has been demonstrated that a major portion of the boundary layer losses occurring in a compressor stage tend to accumulate in the hub and tip regions of the stage annulus. When these boundary layer losses increase under conditions of high stage work, then the compressor will tend to surge, and undesired blade vibration may be induced.

It is, accordingly, another object of the invention to provide improved means to remove the low energy boundary layer of air at the hub section of the annulus in a stage of an axial-flow compressor.

A further object of the invention is the provision, in an axial-flow compressor comprising an assembly of hollow stationary vanes which are disposed downstream of a rotating blade row thereof, of means for allowing the low velocity boundary air accumulating along the hub to flow from the rotating blade row under the shroud of the following hollow stationary vanes and thence through the hollow vanes to a region outside of the compressor annulus.

These and other objects are effected by the invention as will be apparent from the following description taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. l is a fragmentary longitudinal view, partly in section, of an axial-flow compressor constructed in accordance with the invention; and

Fig. 2 is a sectional view of an individual hollow vane element, taken along the line IIII of Fig. 1.

Referring to Fig. l of the drawing, an axial-flow compressor as here disclosed may comprise a cylindrical casing structure 11 having suitably supported therein a front bearing 12 and a rear bearing 13, in which is journaled a rotor 14. A plurality of axially spaced disc portions 15, 16, 17, 18 and 19 are carried on the rotor 14, and are adapted to have mounted thereon groups or stages of radial blades indicated, respectively, by the reference characters 20, 21, 22, 23 and 24. These stages of compressor blades are adapted to be rotated through an annular converging passage extending from an inlet 25 to a discharge outlet 26, and are cooperative with corresponding stages of stationary radially inwardly extending hollow vanes 27, 28, 29 and 30 for compressing air in the usual well-known manner. An annular array of conventional radial guide vanes 32 is mounted in the inlet 25 in advance of the first stage of rotor blades 20.

According to the invention, each of the hollow stationary guide vanes interposed between the stages of rotor blades has formed therein a passage, as indicated 2,831,629 Patented Apr. 22, 1958 by the reference character 33 with respect to each of the vanes 27, one of which is here referred to as representative of all the stationary vanes embodying the same features of the invention. An annular, apertured shroud 34 is provided for interconnecting the inner ends of the hollow vanes 27. A series of circumferentially spaced openings 35 are formed in this shroud, the respective passages 33 being arranged to communicate with the openings. The outer ends of the passages 33 may communicate with the atmosphere by way of openings formed in the casing structure, as shown, or with any suitable vent connection. A radially inwardly extending annular sealing flange 38 is formed on the shroud 34 in alignment with the trailing edges of the vanes 27, and 00- operates in slightly spaced relation with an annular shoulder 39 carried by the succeeding blade supporting disc portion, in this case the disc portion 16, for facilitating fiow'of boundary layer air from surfaces 20a along the hub portions adjacent the rotary blades 20.

It will be understood that the hollow vanes 28, 29 and 30 of succeeding compressor stages are similarly constructed and are operative in the manner just explained to extract boundary layer air from the regions adjacent hub surfaces of all of the rotating stages of the compressor. With the boundary layer of air withdrawn to minimize any tendency of low velocity air to accumulate at each hub stage of the compressor, the desired fiow pattern with relation to the compressor blading is maintained and compressor surging and blade vibration problems are thus minimized.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof.

What is claimed is:

1. In an axial-flow compressor, a rotary element having a hub portion, a plurality of circumferentially spaced radial blades mounted on said hub portion, a plurality of radial stationary guide vanes mounted downstream of said blades for receiving air driven therepast, each of said guide vanes having a vent passage with an inner opening disposed closely adjacent said hub portion for extracting local accumulations of boundary layer air, an annular shroud mounted on the inner ends of the guide vanes, and an inwardly extending annular flange formed on said shroud, said shroud having circumferentially spaced apertures communicating with the respective pas sages in the guide vanes.

2. In an axial-flow compressor, a rotary element having a hub portion, a plurality of circumferentially spaced radial blades mounted on said hub portion, a plurality of radial stationary guide vanes mounted downstream of said blades for receiving air driven therepast, each of said guide vanes having a vent passage with an inner opening disposed closely adjacent said hub portion for extracting local accumulations of boundary layer air, an annular apertured shroud having an inwardly extending annular flange, said shroud being carried on the vanes, and a succeeding compressor stage including a second hub portion and radial blades carried by the rotary element, said succeeding compressor stage being disposed adjacent the downstream side of the stationary guide vanes carrying the shroud, said second hub portion including an annular shoulder projecting into alignment with the annular flange of the shroud for facilitating flow of boundary layer air from the first-named hub portion into the vent passages of the guide vanes.

3. In an axial-flow compressor, a rotary element having a hub portion, a plurality of circumferentially spaced radial blades mounted on said hub portion, and a plurality of radial stationary guide vanes mounted downstream of said blades for receiving air driven therepast, each of a 3 said guide vanes having a vent passage with an inner References Cited inthe file of this patent opening disposed closely adjacent said hub portion for UNITED STATES PATENTS extracting local accumulations of boundary layer air, and sealing means interposed between said hub portion 1,

and the downstream side of said vanes for facilitating 5 such extraction.

Notice of Adverse Decision in Interference In Interference N 0. 92,357 involv ing Patent N 0. 2,831,629, G. E. Giacchine, COMPRESSOR APPARATUS, final judgment adverse to the patentee was rendered May 8, 1962, as to claim 1 [Ofiicz'al Gazette May 18, 11965.] 

